I had this same issue. What micro SD card are you using with your contour +2?
I used mine in mammoth this past Christmas where it had epic powder conditions. I had some of my best runs ever...thought that the contour recorded all of it. Since you can only playback the footage on a computer (tv at cabin didn't have HDMI), I had to wait until I got home. I came to find that only a handful of videos were there. It was missing over 10 videos. I was soooo bummed out and pissed. All the good powder videos weren't there...
I contacted contour, and they thought that I had a defective camera, and suggested I send it back to them. Thankfully, I purchased the camera from dogfunk and was able to do a quick exchange. However, when trying to reformat the second camera, it turned into a brick. That is, the camera would not turn on at all. I was really frustrated this time. I was thinking of going with a GoPro, but loved the convenience of the contour's big record slide bar on the mountain (also don't look like a telletubby). Therefore, I gave a third go around with dogfunk for a new camera. Third camera had issues with footage recorded onto micro SD card too.
Found out that the contour+2 has issues recording files with certain brand micro sd cards, class ratings, and size of the card. Has issues with certain 32 GB and class 10 cards. Found this info on contour's support forum from other customers with similar issues. Mine didn't work with a Sandisk 32 GB Ultra, class 10 UHS well at all. I ended up using a Samsung 16 GB, class 6 micro SD card, and the camera has worked flawlessly since then. The card is plenty fast enough with class 6 to record HD footage.
You might want to use a different micro SD card, if your files are not there at the end of the day. Hope this helps.